Tottenham manager Andre Villas-Boas admitted each goal his side conceded in their 4-1 defeat against Inter Milan felt like a "knife in the back", as he conceded his team had to dig deep to secure a Europa League quarter-final spot after an away-goals win.

Holding what seemed to be a dominant 3-0 lead from the first leg at White Hart Lane, a shaky Tottenham badly missed the suspended Gareth Bale as they so nearly succumbed to what would have been the most remarkable comeback in the short history of the Europa League competition.

In the end, Emmanuel Adebayor's extra time away goal at the San Siro proved to be enough to secure their nervous passage to the last eight, leaving their manager to reflect on a night that so nearly ended in despair.

"Every goal was a boost of motivation for them and knife in the back for us," Villas-Boas told reporters at the San Siro. "When the mind does not work, everything becomes a catastrophe.

"What happened to us tonight was what happened to Inter in London. They are not as bad as their performance in London and we're not as a bad as the performance showed today.

"I didn't underestimate the task we had and I don't think the players did either. We gambled to get the away goal and it was difficult in the end. This was a great lesson for us and something we can learn from.

"I always believed in my players. The desire to reach the last eight of the competition was always there, even in extra-time and that has to be an excellent sign for us. We have played teams like Lazio, Lyon and Inter. It's fantastic satisfaction and achievement to be in the quarters."

Villas-Boas refused to be drawn on the future of stand-in skipper William Gallas after he endured another disastrous night at the heart of the Tottenham defence, as the Spurs boss preferred to highlight the positives ahead of Sunday's vital Premier League clash with Fulham.

"We have responded well to the Thursday and Sunday fixtures this season and we have to try and do the same again," added Villas-Boas. "We have players who did not play tonight who can come in, but I have no doubt about the fitness of my players."